Dahl salt-sensitive and salt-resistant rats were fed either a low salt (0.3% NaCl) control diet or a high salt (8% NaCl) diet to produce hypotension in the sensitive group. Sodium transport was measured by sodium efflux method in thymocytes in either buffer or serum. Intracellular electrolytes were also measured. Results to date indicate no differences in the transport activities or intracellular sodium between sensitive and resistant groups on the low salt diet. On the high salt diet the sensitive rats had a higher cell sodium content. The effects of high salt on transport rates are being assessed.